The subject matter disclosed herein relates to valves. More specifically, the subject matter disclosed herein relates to butterfly valves with pneumatic actuation.
A typical butterfly valve is controlled by a pneumatic actuator. The actuator includes a piston positioned in a cylinder. The piston is connected to a linkage assembly that converts linear motion of the piston in the cylinder to rotary motion of the shaft. The shaft is, in turn connected to a butterfly disc located in a valve body or other flow structure. Rotation of the shaft, via the linkage assembly, rotates the butterfly disc in the valve body, thus opening or closing the valve.
In a typical butterfly valve, the valve body is connected to an actuator body of the pneumatic actuator, with an actuator central axis and a valve body central axis arranged coplanar and in some instances parallel to each other. In such configurations, the actuator is, in effect, cantilevered off the valve body. As such, the actuator is susceptible to vibrations during operation. The actuator can exhibit vibration amplitudes high enough to result in binding of, damage to, or failure of the linkage system and, in turn, failure of the butterfly valve.